Low pry seismic fitting

ABSTRACT

Applicant has disclosed a seismic fitting, and related method, to attach a cable to a structure (e.g., a concrete ceiling, wall or beam of a commercial building). In the preferred “apparatus” embodiment, the seismic fitting, when anchored, comprises: a base with a substantially circular footprint; a substantially circular inner channel, in the base, housing a midsection of cable (preferably wire rope); at least two cable exits in the inner channel, wherein the cable exits are chamfered to prevent and radially equidistant from one another; and a fastener (e.g., a concrete anchor), extending through the entire base, and having one end anchored in concrete; wherein opposite ends of the cable extend beyond the channel and fitting.

RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationSer. N. 62/311,592, entitled “LOW PRY SEISMIC FITTING,” filed Mar. 22,2016. Applicant incorporates that prior application by reference in itsentirety.

FIELD OF INVENTION

This invention relates to seismic fittings.

BACKGROUND OF INVENTION

Seismic retrofitting (a.k.a. seismic fitting) is typically considered “. . . the modification of existing structures to make them moreresistant to seismic activity, ground motion, or soil failure due toearthquakes. With better understanding of seismic demand on structuresand with our recent experiences with large earthquakes near urbancenters, the need of seismic retrofitting is well acknowledged. Prior tothe introduction of modern seismic codes in the late 1960s for developedcountries (US, Japan etc.) and late 1970s for many other parts of theworld (Turkey, China etc.), many structures were designed withoutadequate detailing and reinforcement for seismic protection. In view ofthe imminent problem, various research work has been carried out.State-of-the-art technical guidelines for seismic assessment, retrofitand rehabilitation have been published around the world—such as theASCE-SEI 41 and the New Zealand Society for Earthquake Engineering(NZSEE)'s guidelines.” Wikipedia,https://en.wikipedia.org/wiki/Seismic_retrofit, January 2017.

Retrofit techniques are applicable for various natural hazards such asearthquakes, tropical cyclones, tornadoes, and severe winds fromthunderstorms.

It is the primary object of this invention to provide an economicalseismic fitting to attach cable, e.g., wire rope, to a structure withinthe lowest allowable limits of prying on the fastener for the fitting.

It is a more specific object to fasten such a low-pry seismic fitting toa commercial structure composed of steel, concrete, wood, or otherbuilding material in a manner that will not damage or weaken the cable,captured by the fitting, but will provide a dampening effect and maximumresistance to cable failure under seismic load conditions.

It is yet another object, commensurate with the above-listed objects, toprovide a durable seismic fitting which evenly distributes the load on acable during seismic loads.

It is still another object to allow for installation of the seismicfitting on site.

SUMMARY OF INVENTION

Applicant has disclosed a Low Pry Fitting (“LPF”) which is specificallydesigned to reduce the prying effect on the fastener. The inventive LPFis a one-piece seismic fitting used to attach cable (e.g., wire rope) toa structure or component of that structure. The fitting does not damageor weaken the cable even when seismic loads push the certified cable tothe cable's breaking strength during natural hazards or forces such asearthquakes, tropical cyclones, tornadoes, and severe winds fromthunderstorms.

In the preferred “apparatus” embodiment, the LPF comprises: asubstantially round, low pry, one-piece device with a raised innerchannel provided for the cable; two chamfered exits from the channel forthe cable located on the centerline of the fastener; and an attachmenthole for attaching the LPF to the structure with a suitable fastener,such as a concrete anchor. The channel has an open bottom. When anchoredto a structure, the fitting captures a midsection of the cable withcable end portions extending beyond the fitting.

The LPF is particularly suited for use in concrete structures (e.g.,concrete ceilings, walls or beams in commercial buildings) usingconcrete anchors as the fitting reduces the prying effect on theconcrete anchor to minimal levels specified in NFPA-13.

DESCRIPTION OF DRAWINGS

The above and other objects of the current invention will become morereadily understood when the following text is read in conjunction withthe accompanying drawings, in which:

FIG. 1 is a side plan view of Applicant's preferred LPF anchored in aconcrete structure (e.g., the illustrated first ceiling in an officebuilding) with portions of the concrete, LPF and a cable broken away;

FIG. 2A is a front perspective view of the LPF;

FIG. 2B is a back perspective view of the LPF;

FIG. 2C is an enlarged view of an encircled cable exit shown in FIG. 2A.

FIG. 3 is a cross-sectional view of the LPF showing both cable exits;

FIG. 4 is a top perspective view of the LPF, anchored in the concretestructure, with a cable (here, e.g., wire rope) running through the LPF.

BRIEF DESCRIPTION OF PREFERRED EMBODIMENTS

Applicant has disclosed a Low Pry Fitting (“LPF”) which can be installedonsite in an economical manner. This LPF is specifically designed toreduce the prying effect on a fastener in concrete applications (e.g.,concrete ceilings, walls or beams in a commercial building, such as anoffice building or a parking garage) when used with a cable (wire rope)restraint system to brace against seismic loads.

As shown in FIGS. 1-4, the preferred LPF 100 comprises: a base 102having a substantially circular outer perimeter; a substantiallycircular inner channel 104 (see FIGS. 2A, 2B), in the base 102, designedto house a midsection of a cable 106 (e.g., the illustrated wire rope);two exits 108 a, 108 b (see FIGS. 2A, 2B, 2C) from the channel 104 forthe cable 106, wherein the exits 108 a, 108 b are located on acenterline of a fastener 112 (e.g., the illustrated concrete wedgeanchor); and an attachment hole or throughbore 114 substantiallyperpendicular to, and extending through, the base 102, for attachment ofthe LPF 100 to a structure 116 (e.g., the illustrated concrete ceilingof an office building) by the fastener 112.

The Merriam-Webster dictionary online (www.merriam-webster.com) definescenterline as “a real or imaginary line that is equidistant from thesurface or sides of something.” As used in this application, the phrase“centerline of the fastener” is defined as an imaginary line equidistantfrom the “side” (not top or bottom) surface of the fastener 112.

As used herein, the term “structure” means something constructed orbuilt of steel, concrete, wood, or other building material.

Chamfered edges 107 a, 107 b at the exits 108 a, 108 b of the fitting100 prevent damage to the outer fibers of the cable 106 (e.g., the wirerope) when under tension. The cable channel 104 provides a positiveentrapment of a midsection of the cable 106 when the LPF is attached toa structure 116 (see FIGS. 1, 4). Cable end portions 118 a, 118 b extendbeyond the cable exits 108 a, 108 b and beyond the fitting 100.

Exits 108 a, 108 b are substantially the same and radially equidistantfrom each other. Thus, the LPF 100 only has to be rotated less than 180degrees prior to inserting the cable 106 during onsite installation ofthe cabling and LPF. A quick peek through inspection hole 120, in thebase 102, can insure the cable 106 is placed in the correct positionwithin the channel 104.

As best seen in FIGS. 2A and 4, the preferred base 102 is flat exceptfor the raised inner channel 104. That channel 104, which preferably hasan open bottom, is adjacent the outer perimeter of base 102.

FIG. 1 illustrates the preferred fastener 112 being an expansion typeconcrete fastener (here, a wedge anchor) embedded in a concretestructure 116.

As explained athttps://www.confast.com/articles/how-to-install-concrete-fasteners.aspx,the steps for installing a wedge anchor in cured concrete is:

-   -   1. Drill hole into the concrete using a carbide tipped bit that        meets ANSI standards. Bit size=anchor diameter when working with        wedge anchors. Drill a hole ½″ deeper than the anchor will        penetrate into the concrete making sure that the minimum        embedment requirements are met. The hole can be drilled while        the fixture is in place. It is important to make sure that the        bit diameter being used will fit through the hole in the        fixture.    -   2. Clean out the hole using a wire brush, compressed air,        vacuum, blow out bulb or another method.    -   3. Put the nut and washer onto the wedge anchor and make sure        that the nut is on the last threads (this will protect the        threads from damage when the wedge anchor is hammered into the        hole in the concrete).    -   4. Insert the wedge anchor through the fixture's hole and into        the hole in the base material. This should be a very tight        fit—use a hammer to complete the installation until the nut and        washer are tight against the fixture. It is important that the        threads go below the surface of either the base material or the        fixture.    -   5. Turn the nut clockwise, until finger tight.    -   6. Using a wrench, turn the nut 3-4 times until snug.

For concrete applications, it is simplest to place the fastener 112before pouring of the concrete.

FIG. 4 shows the LPF 100, anchored to the concrete structure 116 (e.g.,the illustrated first floor's ceiling 116 in an office building), withwire rope ends 118 a, 118 b. Each cable (wire rope) end can be used tobrace structural components or devices (e.g., fire sprinkler systems,HVAC systems and plumbing pipes) in any suitable manner. For example,lateral bracing, longitudinal bracing or 4-way bracing could be used tobrace a pipe (not shown).

Base 102 has a circular footprint, when anchored by fastener 112 (seeFIGS. 1, 4). Cable 106 is captured in channel 104 when the LPF 100 isanchored to the structure (here, the illustrated concrete ceiling).

By allowing the load force to be distributed equally on both sides ofthe installed fastener 112, due to the alignment of the pressure pointsof the cable (wire rope) 106 with the centerline of the fastener 112,the prying effect on the fastener 112 is lessened during seismic events,cyclones, tornadoes, or severe winds from thunderstorms.

Using the LPF 100 and certified cable 106 (preferably wire rope) willallow for the code compliant tensioned sway control bracing ofstructural components, with the minimal prying effect applied to thefastener 112.

The LPF 100 is used to achieve compliance with various building codesand standards including, but not limited to, NFPA-13 and ASCE-7 forbracing of structural components or devices to resist damage due toseismic activity when using cable (wire rope) as the bracing element ina tension only environment.

For example, NFPA-13 describes a preferred order of where to fasten aseismic fitting in a commercial building: the ceiling, a wall, and abeam. That is the same preferred order for the LPF 100.

The LPF 100 is designed primarily to be anchored in a concrete ceiling(e.g., ceiling 116). When the LPF is in use, one cable end portion(e.g., 118 b) is connected to the other cable portion (e.g., 118 a) by acrimped sleeve 122 (see FIG. 4).

The LPF 100 is also applicable to resist damage due to other naturalhazards such as tropical cyclones, tornadoes, and severe winds fromthunderstorms.

The LPF's reduction in the prying effect on the fastener 112 would alsoapply to the prying forces experienced in steel, wood, or other buildingmaterials. The LPF 100 would allow for smaller diameter fasteners to beused in those applications due to the low prying effect that thesefittings provide.

Applicant's invention can also be thought of in method terms. Inbroadest language, the method comprises:

-   -   a. housing a midsection of cable within a substantially circular        inner channel of a seismic fitting;        -   i. wherein the channel has an open bottom;    -   b. anchoring the seismic fitting to a structure; and    -   c. whereby the midsection of cable is captured between the        structure and the open-bottom inner channel.

A narrower method comprises:

-   -   a. anchoring a seismic fitting to a structure (e.g., composed of        steel, concrete, wood, or other building material) via an anchor        extending perpendicular to the fitting, and entirely through a        central throughbore of the fitting, with opposite ends of the        anchor extending beyond the fitting;    -   b. wherein the seismic fitting comprises:        -   i. a base with a substantially circular footprint;        -   ii. the base has a front and a back;        -   iii. a substantially circular inner channel in the base and            adjacent an outer perimeter of the base; and        -   iv. at least two cable exits from the inner channel, wherein            the at least two cable exits are radially equidistant from            each other, and wherein the at least two cable exits are            located on a centerline of a concrete anchor; and    -   c. housing a midsection of cable, within the channel, with two        opposite end portions of the cable extending beyond the cable        exits and the fitting.

It should be understood that obvious structural modifications can bemade without departing from the spirit or scope of the invention. Forexample, though perhaps not as secure: a sleeve anchor—used in concrete,brick or block—could be utilized as fastener 112. Accordingly, referenceshould be made primarily to the following claims rather than theforegoing specification to understand the scope of the invention.

What is claimed is:
 1. A seismic fitting comprising: a. a base, of thefitting, having a substantially circular outer perimeter; b. the basehas a front and a back; c. a substantially circular inner channel, inthe base, adapted in size and shape to house a midsection of wire rope;d. two wire rope exits from the inner channel, e. a throughboresubstantially perpendicular to, and extending through the center of, thebase; and f. wherein the throughbore is adapted in size and shape for aconcrete anchor to extend though the entire throughbore.
 2. The seismicfitting of claim 1 further comprising chamfered edges at the exits toprevent damage to the wire rope when the wire rope cable is undertension.
 3. The seismic fitting of claim 1 wherein the concrete anchoris a wedge anchor.
 4. The seismic fitting of claim 1 wherein the twoexits are 180° apart in the channel.
 5. An apparatus comprising: a. aseismic fitting comprising: i. a base with a substantially circularfootprint; ii. the base has a front and a back; iii. a substantiallycircular channel, in the base, wherein the channel houses a midsectionof a cable; iv. two cable exits in the inner channel, wherein the cableexits are radially spaced apart by 180° ; and v. a throughboreperpendicular to, and extending through the center of, the base; b. aconcrete anchor, extending through the entire throughbore, and havingone end anchored in concrete; c. the concrete anchor is secured to thefitting; and d. wherein two end portions of the cable extend beyond thecable exits and the fitting.
 6. The seismic fitting of claim 5 furthercomprising chamfered edges at the cable exits to prevent damage to thecable when the cable is under tension.
 7. The seismic fitting of claim 5wherein the cable comprises a wire rope.
 8. The seismic fitting of claim5 wherein the concrete anchor is a wedge anchor.
 9. A method of securinga cable to a structure, the method comprising: a. anchoring a seismicfitting to a structure via an anchor extending perpendicular to thefitting and entirely through a central throughbore of the fitting withopposite ends of the anchor extending beyond the fitting; b. wherein theseismic fitting comprises: i. a base with a substantially circular outerperimeter; ii. the base has a front and a back; iii. a substantiallycircular channel in the base and adjacent the perimeter; and iv. atleast two cable exits from the inner channel, wherein the at least twocable exits are radially equidistant from each other, and wherein the atleast two cable exits are located on a centerline of the anchor; and c.housing a midsection of cable, within the channel, with two end portionsof the cable extending beyond the cable exits and the fitting.
 10. Themethod of claim 9 wherein the cable comprises a wire rope.
 11. Themethod of claim 9 wherein the at least two cable exits have chamferededges to prevent damage to the wire rope when the wire rope is undertension.
 12. The method of claim 9 wherein the anchor is a concretewedge anchor and the structure is concrete.
 13. The method of claim 9wherein the at least two exits are radially equidistant in the channel.14. A method comprising: a. housing a midsection of cable within asubstantially circular inner channel of a seismic fitting; i. whereinthe channel has an open bottom; b. anchoring the seismic fitting to astructure; and c. whereby the midsection of cable is captured betweenthe structure and the open-bottom inner channel.